Micromorphological and chemotaxonomical traits of Micromeria croatica (Pers.) Schott

A study on the types and distribution of trichomes, pollen morphology, chemical composition of essential oil (analyzed by GC-FID and GC/MS), and the content of macroelements (Na, K, Ca, and Mg) and trace elements (B, Fe, Cu, Mn, Zn, Al, Pb, Cr, Cd, Ni, Hg, and As) analyzed by ICP-AES (=inductively coupled plasma atomic emission spectroscopy) was conducted on Micromeria croatica (Pers.) Schott. Non-glandular trichomes, peltate trichomes (typical hairs of Lamiaceae), small capitate trichomes (composed of one basal epidermal cell and one head cell), and larger capitate trichomes (composed of one basal epidermal cell, two to three stalk cells, and one head cell with subcuticular space) were observed on leaves, stems, the calyx, and corolla. Pollen of M. croatica had six apertures (hexacolpate) which were set in the equatorial pollen belt (zonocolpate) and showed medium reticulate ornamentation (hetrobrochate type). The essential oil contained from 27 to 39?constituents, the most representative of which were caryophyllene oxide and E-caryophyllene. Among the investigated macroelements, the content of K was highest (8730-10080?mg/kg). The content of trace elements ranged from 0.12?mg/kg (Cr) to 78.00?mg/kg (Fe), while the content of Cd, Ni, Hg, and As were lower than the limit of quantification.     

Resistin inhibits essential functions of polymorphonuclear leukocytes

The serum levels of resistin, a 12-kDa protein primarily expressed in inflammatory cells in humans, are increased in patients with chronic kidney disease and in those with diabetes mellitus. Both groups of patients have an increased risk of infections mainly as a result of disturbed polymorphonuclear leukocyte (PMNL) functions. Therefore, we investigated the influence of resistin on human PMNLs. Serum resistin concentrations were determined with a sandwich enzyme immunoassay. Using PMNLs from healthy subjects, chemotaxis was tested by the under-agarose method. Flow cytometric assays to measure oxidative burst and phagocytosis were conducted in whole blood. The uptake of deoxyglucose was determined as measure of the PMNL activation state. The activity of intracellular kinases was assessed by Western blotting and by in vitro kinase assays. Resistin inhibited PMNL chemotaxis and decreased the oxidative burst stimulated by Escherichia coli and by PMA, but did not influence PMNL phagocytosis of opsonized E. coli and PMNL glucose uptake. The inhibition of PMNLs by resistin was observed at concentrations found in serum samples of uremic patients, but not in concentrations measured in healthy subjects. Experiments with specific signal transduction inhibitors and measurements of intracellular kinases suggest that PI3K is a major target of resistin. In conclusion, resistin interferes with the chemotactic movement and the stimulation of the oxidative burst of PMNL, and therefore may contribute to the disturbed immune response in patients with increased resistin serum levels such as uremic and diabetic subjects.     

Metallothionein expression and tissue metal kinetics after partial hepatectomy in mice

To better elucidate previous results showing that partial hepatectomy noticeably changes the tissue content of zinc, calcium, magnesium, and iron(II) ions in regenerating the liver, thymus, and spleen, we report on the correlation of these metal tissue kinetics in these organs with the expression of metallothionein-I+II (MT-I+II) proteins and MT-I mRNA in early postoperative period (1, 2, 6, 12, and 24 h) after one-third hepatectomy (pHx). The results showed that 2 h after pHx the regenerating liver accumulated Zn²⁺, Ca²⁺, Mg²⁺, and Fe²⁺ ions while decreasing the concentration of all these metals in the spleen and of Zn²⁺ in the thymus. On the 24th h, a new high accumulation of Zn²⁺ and Ca²⁺ was seen in the regenerating liver and of Zn²⁺, Ca²⁺, and Fe²⁺ in the spleen. Simultaneously, MT-I mRNA increased in the liver and spleen. In hepatocytes and on several spleen and thymus mononuclear lymphatic cells, the increased expression of MT proteins was found mainly in the cytoplasm and nuclei. The areas expressing MTs in regenerating liver inversely correlated with those containing apoptotic cells, suggesting that these proteins participate in tissue restoration through reduction or increase of metal ions after injury to the liver.     

Seasonal variation in CO2 efflux of stems and branches of Norway spruce trees

BACKGROUND AND AIMS: Stem and branch respiration, important components of total forest ecosystem respiration, were measured on Norway spruce (Picea abies) trees from May to October in four consecutive years in order (1) to evaluate the influence of temperature on woody tissue CO2 efflux with special focus on variation in Q10 (change in respiration rate resulting from a 10 degrees C increase in temperature) within and between seasons, and (2) to quantify the contribution of above-ground woody tissue (stem and branch) respiration to the carbon balance of the forest ecosystem. METHODS: Stem and branch CO2 efflux were measured, using an IRGA and a closed gas exchange system, 3-4 times per month on 22-year-old trees under natural conditions. Measurements of ecosystem CO2 fluxes were also determined during the whole experiment by using the eddy covariance system. Stem and branch temperatures were monitored at 10-min intervals during the whole experiment. KEY RESULTS: The temperature of the woody tissue of stems and branches explained up to 68% of their CO2 efflux. The mean annual Q10 values ranged from 2.20 to 2.32 for stems and from 2.03 to 2.25 for branches. The mean annual normalized respiration rate, R10, for stems and branches ranged from 1.71 to 2.12 micromol CO2 m(-2)s (-1) and from 0.24 to 0.31 micromol CO2 m(-2) s(-1), respectively. The annual contribution of stem and branch CO2 efflux to total ecosystem respiration were, respectively, 8.9 and 8.1% in 1999, 9.2 and 9.2% in 2000, 7.6 and 8.6% in 2001, and 8.6 and 7.9% in 2002. Standard deviation for both components ranged from 3 to 8% of the mean. CONCLUSIONS: Stem and branch CO2 efflux varied diurnally and seasonally, and were related to the temperature of the woody tissue and to growth. The proportion of CO2 efflux from stems and branches is a significant component of the total forest ecosystem respiration, approx. 8% over the 4 years, and predictive models must take their contribution into account.     

Rosella: a fluorescent pH-biosensor for reporting vacuolar turnover of cytosol and organelles in yeast

We have developed a method for monitoring autophagy using Rosella, a biosensor comprised of a fast-maturing pH-stable red fluorescent protein fused to a pH-sensitive green fluorescent protein variant. Its mode of action relies upon differences in pH between different cellular compartments and the vacuole. Here we demonstrate its utility in yeast (Saccharomyces cerevisiae) by expression in the cytosol, and targeting to mitochondria or to the nucleus. When cells were cultured in nitrogen depleted medium, uptake of the compartment labelled with the biosensor (i.e., cytosol, mitochondria, or nucleus) into the vacuole was observed. We showed that this vacuolar uptake was, for cytosol and mitochondria, an ATG8-dependent process while the uptake of the nucleus was significantly reduced in the absence of Atg8p and can be said to be partially ATG8-dependent. We further demonstrated the value of the biosensor as a reporter of autophagy by employing fluorescence-activated cell sorting of discrete populations of cells undergoing autophagy.     

Variation in Honey Bee Gut Microbial Diversity Affected by Ontogenetic Stage,Age and Geographic Location

Social honey bees, Apis mellifera, host a set of distinct microbiota, which is similar across the continents and various honey bee species. Some of these bacteria, such as lactobacilli, have been linked to immunity and defence against pathogens. Pathogen defence is crucial, particularly in larval stages, as many pathogens affect the brood. However, information on larval microbiota is conflicting.Seven developmental stages and drones were sampled from 3 colonies at each of the 4 geographic locations of A. mellifera carnica, and the samples were maintained separately for analysis. We analysed the variation and abundance of important bacterial groups and taxa in the collected bees.Major bacterial groups were evaluated over the entire life of honey bee individuals, where digestive tracts of same aged bees were sampled in the course of time. The results showed that the microbial tract of 6-day-old 5th instar larvae were nearly equally rich in total microbial counts per total digestive tract weight as foraging bees, showing a high percentage of various lactobacilli (Firmicutes) and Gilliamella apicola (Gammaproteobacteria 1). However, during pupation, microbial counts were significantly reduced but recovered quickly by 6 days post-emergence. Between emergence and day 6, imago reached the highest counts of Firmicutes and Gammaproteobacteria, which then gradually declined with bee age. Redundancy analysis conducted using denaturing gradient gel electrophoresis identified bacterial species that were characteristic of each developmental stage.The results suggest that 3-day 4th instar larvae contain low microbial counts that increase 2-fold by day 6 and then decrease during pupation. Microbial succession of the imago begins soon after emergence. We found that bacterial counts do not show only yearly cycles within a colony, but vary on the individual level. Sampling and pooling adult bees or 6th day larvae may lead to high errors and variability, as both of these stages may be undergoing dynamic succession.     

Glutathione–ascorbic acid redox cycle and thioredoxin reductase activity in the digestive tract of Leptinotarsa decemlineata (Say)

In view of the antioxidant role of glutathione (GSH) and ascorbic acid (AA), we have examined capacity of the GSH–AA redox cycle in relation to oxidative stress effects in the midgut of the Colorado potato beetle Leptinotarsa decemlineata. Adult gut harbors a higher capacity to cope with oxidative stress than the larval gut. Protein carbonylation was pronounced in the wall of anterior larval midgut and was generally lower in the food digest than in the gut wall. Restriction of oxidative stress effects in anterior gut lumen manifested by lipid peroxidation and protein carbonylation is interpreted as a mechanism favoring digestion and absorption in the posterior midgut. Presence of high GSH in the posterior midgut and AA in both posterior and anterior midguts of adults points to higher utility of the GSH–AA redox system in limiting oxidative stress to manageable levels. The presence, gene expression and activity of thioredoxin reductase (TrxR) were demonstrated for the first time in L. decemlineata which was markedly higher in the anterior than in the posterior midgut in both stages. It is probably central to the maintenance of reduced GSH levels in the whole gut, despite a GSSG/2GSH redox potential tending towards oxidizing ranging from ?183.5 to ?124.4 mV. Glutathione-dehydroascorbate reductase (G_DHAR) activity was markedly augmented in adult gut compared with larva, pointing to a more efficient conversion of dehydroascorbate (DHA) to AA. Also, ascorbate peroxidase (APOX) activity was significantly elevated in all gut compartments of adult except the wall of posterior midgut. The results emphasize the potential importance and role of the GSH–AA redox cycle as a defense strategy against oxidative stress in the gut of L. decemlineata.     

Computational analysis of lung deformation after murine pneumonectomy

In many mammalian species, the removal of one lung (pneumonectomy) is associated with the compensatory growth of the remaining lung. To investigate the hypothesis that parenchymal deformation may trigger lung regeneration, we used microCT scanning to create 3D finite element geometric models of the murine lung pre- and post-pneumonectomy (24 h). The structural correspondence between models was established using anatomic landmarks and an iterative computational algorithm. When compared with the pre-pneumonectomy lung, the post-pneumonectomy models demonstrated significant translation and rotation of the cardiac lobe into the post-pneumonectomy pleural space. 2D maps of lung deformation demonstrated significant heterogeneity; the areas of greatest deformation were present in the subpleural regions of the lobe. Consistent with the previously identified growth patterns, subpleural regions of enhanced deformation are compatible with a mechanical signal – likely involving parenchymal stretch – triggering lung growth.